Each channel has a bias potentiometer which is used to set
the bias. The bias should be set so that after one hour operation,
with the cover on, each channel should run about 50 deg C. in
a 25 deg C. room. This means that a ordinary room temperature
the heat sinks should be at the temperature where you can put
your hand on them for about 10 seconds.
The critical thing is not to accidentally find yourself biased at too
high a current figure, otherwise you risk blowing the channel up.
You must monitor the current draw of the channel, best done
by reading the voltage across one of the .33 ohm emitter
resistors on the output stage. Since it takes time for the amp
to warm up and the bias is somewhat temperature dependent,
you want to adjust the value of the bias very slowly, and then
wait while monitoring the current draw.
If the channel is running cold, then you increase the bias above
the existing value by a little bit. Then you wait.
Did I mention that there are hazardous voltages and stuff
inside the amp? If you don't know to do this safely, then don't
try it - find a technician and buy him a 6 pack.
the bias. The bias should be set so that after one hour operation,
with the cover on, each channel should run about 50 deg C. in
a 25 deg C. room. This means that a ordinary room temperature
the heat sinks should be at the temperature where you can put
your hand on them for about 10 seconds.
The critical thing is not to accidentally find yourself biased at too
high a current figure, otherwise you risk blowing the channel up.
You must monitor the current draw of the channel, best done
by reading the voltage across one of the .33 ohm emitter
resistors on the output stage. Since it takes time for the amp
to warm up and the bias is somewhat temperature dependent,
you want to adjust the value of the bias very slowly, and then
wait while monitoring the current draw.
If the channel is running cold, then you increase the bias above
the existing value by a little bit. Then you wait.
Did I mention that there are hazardous voltages and stuff
inside the amp? If you don't know to do this safely, then don't
try it - find a technician and buy him a 6 pack.
Zen Mod said:
I've already found them by myself.
Thanks anyway.
About the warmth of handles and front panel, it sounds strange to me that it is so high, I own other amps including a valvestate with eight 6550 and handless and panel remain cold.
Unfortunately, this is my first experience with a class A: sorry if I annoy you with silly questions, I will try to avoid them in future.
Greets,
Nino
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.